Angular 6：TypeError：无法读取未定义的属性“值”

Question

我正在创建一个简单的表单来提交数据、电子邮件、城市名称和酒店名称，当我点击提交时出现此错误：

AboutComponent.html:79 错误类型错误：无法读取属性“值” 未定义的

这是我所拥有的： 评论.js

// Comments Schema

const CommentsSchema = mongoose.Schema({

  email: {
    type: String,
    required: true
  },
  name: {
    type: String,
    required: true
  }
},{
    collection: 'comments'
});

const Comments = module.exports = mongoose.model('Comments', CommentsSchema);

组件.ts

addReview(email, name) {
    this.moviesService.addReview(email, name).subscribe(success => {
      this.flashMessages.show('You are data we succesfully submitted', { cssClass: 'alert-success', timeout: 3000 });
      // get the id
      this.activeRouter.params.subscribe((params) => {
        // tslint:disable-next-line:prefer-const
        let id = params['id'];
        this.moviesService.getComments(id)
          .subscribe(comments => {
            console.log(comments);
            this.comments = comments;
          });
      });
    }, error => {
      this.flashMessages.show('Something went wrong', { cssClass: 'alert-danger', timeout: 3000 });
    });
  }

html

<form [formGroup]="angForm" class="form-element">
          <div class="form-group form-element_email">
            <input type="email" class="form-control info" placeholder="Email" formControlName="email" #email (ngModelChange)="onChange($event)">
            </div>
            <div *ngIf="angForm.controls['email'].invalid && (angForm.controls['email'].dirty || angForm.controls['email'].touched)"
                class="alert alert-danger">
                <div *ngIf="angForm.controls['email'].errors.required">
                  Email is required.
                </div>
              </div>
        <div class="input-group mb-3 form-element_city">
          <select class="custom-select" id="inputGroupSelect01">
            <option selected *ngFor="let city of cities" [ngValue]="city.name" #name>{{city.name}}</option>

          </select>
        </div>
        <div class="input-group mb-3 form-element_hotel">
            <select class="custom-select" id="inputGroupSelect01">
              <option selected *ngFor="let hotel of hotels" [ngValue]="hotel.name" #name>{{hotel.name}}</option>

            </select>
          </div>
          <div class="form-group">
              <button type="submit" (click)="addReview(email.value, name.value)" class="btn btn-primary btn-block form-element_btn" [disabled]="!validEmail">ACCEDER</button>
            </div>
      </form>

service.ts

 addReview(email, name): Observable<any> {
    const uri = `${apiUrl + this.addCommentsUrl}`;
    const obj = {
      email: email,
      name: name
    };
    return this.http.post(uri, obj);
  }

注意：当我删除名称时，一切正常，但我还需要将城市名称和酒店名称与电子邮件一起插入到我的数据库中。

我的代码有什么问题？

Answer 1

我认为 templateRef var 应该在 select 元素而不是 option 元素上。

改为这个

<option selected *ngFor="let city of cities" [ngValue]="city.name" #name>{{city.name}}</option>

你可以试试这个：

<select class="custom-select" id="inputGroupSelect01">

附带说明 templateRef 变量名称对于每个选择元素应该是唯一的。您不能对两个不同的元素使用相同的变量。

在此处查看#name：

1. <option selected *ngFor="let city of cities" [ngValue]="city.name" #name>{{city.name}}</option>

2. <option selected *ngFor="let hotel of hotels" [ngValue]="hotel.name" #name>{{hotel.name}}</option>

如果有帮助，请告诉我！